JPS5984303A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent incidence of erase omission and deterioration of picture quality by using a magnetic head for recording and reproducing also as an erase head. CONSTITUTION:It is arranged that a magnetic head for recording and reproducing is also used as an erase head. To prevent the beat interference from occurring and erase rate from dropping when the constitution for this combined use is provided, an erase signal SER is supplied at the time of erasing through an oscillator 34 for erase signal under a condition where a sheet-like recording medium is rotated at a speed which is lower than that of the recording and reproducing time. Moreover, the frequency of the erase signal SER and the reduction ratio of the rotating speed of a motor 11 are selected, so that the reproduced spectrum of the erase signal SER exists at the outside of an FM recording band at the time of reproduction. In this way, no erase omission takes place and deterioration of picture quality can be prevented even when a jacket is inserted under an off-center condition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an information signal recording and reproducing apparatus using a sheet-like recording medium that does not use a photosensitive film and is suitable for use in so-called electronic cameras.

BACKGROUND TECHNOLOGY AND PROBLEMS FIG. 1 shows the conceptual structure of an electronic still camera. Inside the camera housing (1), like a normal camera, there is a lens system (2), an iris mechanism (3), and a shutter mechanism (
4), (5), mirrors (6), (7), and a viewfinder (8) are provided. In addition, optical sensors such as COD (9) are unique to electronic cameras.
, a signal recording/reproducing circuit αQ1, and a motor 01) for rotating the magnetic disk.

The jacket α→ that houses the rotating magnetic disk (6) is
It is structured to be inserted into the main body of the camera housing (1) from the outside. The magnetic disk α'4 has one track per track.
Methyl images are recorded concentrically. A reproduction of this image can be viewed on an ordinary television receiver.

Methyl images can be played back using a playback-only machine and by inserting a jacket C141 into it, but the camera in this example is configured as an electronic camera with a playback function.
Therefore, if the jacket α→ is inserted into the electronic camera and set to playback mode, the output terminal αυ outputs a video signal for still images, which is the same as a normal television signal.

0Q is a clock generator that drives the optical sensor (9), etc.
H is a magnetic head for recording and reproducing, and this magnetic head H is movable in the radial direction of the disk (6) as shown in FIG. α is the i9 pulse motor, and 0 o'clock is the gear for head feeding. In this example, 16 steps/rotation pulse smoke (one gear is used, and the magnetic head H moves approximately 100μ with one revolution of pulse motor α). do.

FIG. 3 shows an example of a magnetic track pattern, in which the magnetic track width Tw is 60μ and the track pitch TP is 100μ.

FIG. 4 shows an example of the frequency spectrum of the still image video signal So recorded by the magnetic head H. The luminance signal Y is FM modulated with a center carrier frequency of 6.0 to 8.0 MHz, and its frequency band is 12.0 MHz. .

It is about MHz. The color signal C is FM modulated at a center carrier frequency of 1.5 to 2.0 MHz and then low-pass converted.
It is superimposed on the luminance signal SY.

Even with such electronic cameras, if you can freely erase the recorded contents of any previously recorded track and record new information on that track, you can freely edit it directly. It is convenient because it can be done, and
Economical.

To do this, an erasing head can be installed inside the electronic camera, but since the electronic camera itself is designed to be compact and the jacket 04 is also very small, an erasing head must be installed in addition to the magnetic head H for recording and playback. In addition to the window hole (14a) shown in Figure 2, there is another window for the erasing head in the jacket α, which is technically difficult because the layout of the drive system must be considered. Providing holes is not a good idea because it requires measures against dust.

In order to solve these problems, it is conceivable to construct the magnetic head (I) so that it can be used not only as a recording and reproducing head but also as an erasing head.

By the way, in this dual-use configuration, the erasing track width is the same as the recording track width, so for example, the jacket α→ may be inserted slightly eccentrically due to poor insertion or insufficient insertion accuracy. Sometimes. Further, even if the insertion is complete, expansion and contraction of the disk (6) may cause the same state as eccentricity.

Therefore, in such a case, even if the magnetic head is partially positioned completely over the recording track, one rotation of the disk θ→ will cause the recording track and erase track to partially overlap, resulting in a shift. , erasure omission occurs in this mismatched section. The section where the deletion is omitted will be double recorded, so
The image in this section is significantly degraded.

OBJECT OF THE INVENTION Accordingly, the present invention prevents deterioration of image quality by preventing erasure from occurring when a magnetic head for recording and reproducing is also used as an erasing head.

SUMMARY OF THE INVENTION Therefore, in the present invention, the magnetic head is slightly shifted toward the outer circumference and the inner circumference of the main turn for recording, respectively, before erasing. Therefore, the number of times of erasure for the same track is selected to be multiple times.

Embodiment Next, an example of the present invention applied to the above-mentioned electronic camera will be described in detail with reference to FIG. 5 and subsequent figures.

FIG. 5 shows an example of the recording/reproducing circuit 01, which includes an optical sensor (
The imaging output of 9) is converted by the encoder into a video signal So having the spectrum shown in Fig. 4A, which is then sent to the magnetic field via the first switch Qυ, the recording amplifier (c), and the recording/playback selector switch 04). The video signal So is supplied to the head H and recorded on a predetermined track. (25) is a reproduction amplifier.

(27) is a speed control system for the motor, and as is well known, it has a phase comparator (28). The clock generator ◇ and vertical synchronization output from the clock generator (29) are supplied via the second frequency generator (29), and the output of the frequency generator (29) is supplied to the frequency divider (29). ) It is supplied after being frequency-divided by K.The phase comparison output is smoothed by a loaf 4 filter 0, and the output is sent to the motor α via the driver 0→.
(2) is supplied as a related control signal. Since the vertical synchronization pulse VD is used as a reference signal, the motor a core is controlled at 600 rotations per second.

The first and second switches QO1@ are used when the magnetic head H is used as an erase head, and are switched in conjunction with each other. 0yu is an oscillator of the erase signal SIR.

By the way, when the magnetic head H for recording and reproducing is also used as an erasing head as described above, since the video signal So to be recorded has a wide band as shown in FIG. 2, wide band erasing is performed. 6.0 to 8 as the cancellation frequency fw
．． If a frequency of 0 MHz is selected, a beat occurs between the erasure signal Sg and the FM brightness signal S color during reproduction, resulting in a significant deterioration of image quality. In order to eliminate beat disturbances during playback,
The erasure frequency fE is the video signal S.

Although it is possible to choose a frequency outside the band of
Not only is it difficult to design the circuit to supply the magnetic head H with the same amount of energy, but also the erasing rate is significantly reduced. In order to prevent a beat disturbance and a decrease in erasing rate when a dual-use configuration is used, an erasing signal is supplied while the sheet-like recording medium is rotated at a lower speed than the rotational speed during recording and reproduction.

In this case, the frequency of the erasing signal and the reduction ratio of the rotational speed may be selected so that the reproduction spectrum of the erasing signal exists outside the FM recording band during reproduction.

Therefore, in the erase mode, the rotational speed N of motor a◇
E is decelerated to 1 during recording and reproduction. In this example, a frequency of 2 fsc (/sc is the color subcarrier frequency, 3.58 Iz in the NTSC system) is used as the erasure signal SER, and at this time, the rotational speed NE of the motor α is the rotational speed during recording and playback. The speed is reduced to NR1. Therefore,
In the erase mode, a reference pulse 1D, which is obtained by lowering the frequency of the vertical synchronization pulse VD to 1, is supplied to the second switch 3 (via the second switch 0').

If one erasure is insufficient for the same track, erasing is performed multiple times (5 to 10 times).

The experiment was repeated 5 to 6 times with good results.

In this way, while selecting the frequency at the time of erasure as 2fsc,
Rotational speed NP of motor α force! When 1NR is selected, the frequency spectrum at the time of reproduction is 3×2fsc as shown in Figure 4B, and the reproduction cancellation frequency is 3×2fsc.Therefore, the reproduction cancellation signal SEP can be seen by comparing with Figure 4A. exists outside the band of the reproduced video signal SO.

Such a high frequency erase signal SEP is transmitted to the magnetic head H.
Since the limit of the reproduction capability of the reproduction amplifier (25) is also much higher, the reproduction level will be less than -40 dB.

Further, when the frequency of the erasure signal SEP is high as described above, the beat frequency with the video signal So becomes high, and there is no beat disturbance.

Next, the relationship between the erasing frequency fEns, rotational speed NEz, and erasing current i1 during erasing and the erasing rate will be explained with reference to FIG. 6 and subsequent figures.

FIG. 6 is a graph showing the relationship between the rotational speed NE during erasing and the erasing rate. In this example, the erasing frequency fr, n is 6.0 RII
Hz, an erase current IE of 100 mA is applied, and the number of erases is 6 times, the signal frequency fR to be erased is 5.
This is the case of 00kHz and 7.0■t. The low frequency signal of 500kHz was recorded because low frequency signals are generally erased. Therefore, if the erasure rate of such a low frequency signal is high, it will be possible to erase the recorded signal from the low range to the high range. This is because it is considered that the signal is almost completely erased in all frequency bands.

Under these conditions, if the rotational speed NR during recording and reproduction is set to the normal speed and the rotational speed NE is sequentially decelerated, the erasing rate improves as the rotational speed Nff1 during erasing becomes slower. Normally, if the erasure rate is -30 dB or less, there is no problem in practice, so the reduction ratio n may be 3 or more.

At this time, the recorded signal with a frequency of 7.0 VIHz is -40
The erasure rate is less than dB.

FIG. 7 is a graph showing the relationship between erase frequency/ER and erase rate measured under three types of erase current II. In the figure, both recording currents are 50 mA % NE = ANR1
The data is when the number of erases is 6 times, the chain line graph shows the erase current II is 100mA, and the solid line graph shows E=13.
0mA1 and the dashed line graph is I E = 150mA
It's time.

As is clear from this graph, the erase current I.

If is selected to be 130 mA or more, sufficient erasure can be achieved with an erasure frequency fF, R of 3 MHz or more.

FIG. 8 is a graph showing the relationship between erase current II and erase rate.
J'-ER=6 MHzSNw=3 NR% This is data when the number of erasures is 6 times and the recording current is 50 mA each.

As mentioned above, and as is clear from this figure, 120~1
If the erase current II is 30 mA or more, even low-frequency signals that are difficult to erase can be sufficiently erased.

As is clear from these graphs, the video signal S during playback
The recording erasing frequency fE is set so that the reproduction erasing frequency fzp exists outside the frequency band of o and a sufficient erasing rate is obtained.
The relationship between n, reduction ratio n, and erase current Ig is determined.

Therefore, if the reduction ratio n1 is increased, the recording frequency ft
n becomes a low frequency, but increasing n causes problems with the stability of the rotational speed N and increases the erasing time')
, it is not preferable to increase the sweet bn because it causes problems such as a longer locking time until the rotational speed is returned to NR. For example, if the output of the clock generator αQ is used as the erase signal SER and the dedicated oscillator (b) is omitted, the frequency fsc or twice this frequency, or the center carrier frequency of FM should be selected. Therefore, in this case, a suitable value for n is 3 or 4.

If you choose B w 3, fEi-2fscsIE
= 200 mA and the number of erasures = 6 times, a sufficient erasure rate can be obtained.

By the way, as an example of erasing the contents recorded on a certain track Tn, there are two cases: searching for and erasing any previously recorded track Tn before removing jacket α◆ from the electronic camera, and After reinsertion, this track Tn may be searched and deleted. In the former case, there is no particular problem, but in the latter case, as mentioned at the beginning, even if the jacket fitting θ is inserted correctly, it is often inserted slightly eccentrically due to mechanical error. If it is inserted in an eccentric state, erasure leakage occurs in some sections during erasing, as described above.

That is, by specifying an erase track after inserting the jacket, the magnetic head H is moved over that track, but even when erasing, the image content of that track must be played back once to confirm whether it is the content that should be erased or not. Therefore, the track to be erased is first played back.

In this case, tracking serve is performed such that the magnetic head H moves to the position where the average value of the reproduced output is maximum.

In this well-known tracking serve, the head feed stops at the position where the average value output is maximum, so if the jacket α→ is installed eccentrically, the track pattern and recorded pattern at the time of erasing will be completely different over the entire circumference. Since they no longer match, if the data is erased in this state, some sections will not be erased.

Erase considering this insertion error/? A turn is determined.

Therefore, in this invention, the number of times of erasure is set as m (m is an even number of 2 or more), and as shown in FIG. i? ! When the magnetic head H is at the position shown by the broken line, the first erasing of the socket is performed by moving the magnetic head H toward the outer periphery by Ts+ from this position, and the erasing of the closed area of the remaining socket is performed in the opposite direction. Tl! This is performed by moving the magnetic head H toward the inner circumference by 2 (TS 2 = 'r81).

In this way, if the position of the magnetic head H for just tracking is shown by the broken line, the erase track width will be (TW+TE
11 +782), so even if the jacket 04 is inserted eccentrically, no erasure will occur. Although the track movement width T1111T82 varies depending on the insertion accuracy of the jacket α→, in the experiment, it was selected as Ts1=Tsz:′6μ. This value corresponds to the head feed amount by one step rotation of the pulse motor 0''I).

Figure 10 shows a control circuit θ that realizes such an erase mode.
This is an example of 1.

The figure shows the case where a three-phase stator winding I, 11-LcK is applied to a two-phase excitation system that uses a 3-phase stator winding motor θ to achieve 16 steps/rotation. t
J: Pulse/warm amplifiers α-O◆ are connected, respectively.
The input/IP pulses distributed as desired by the pulse distributor (c) are supplied to these as rotation control pulses.

An erase mode pulse Pg is supplied to the terminal θQ.

Erasing mode A'rus pg is the first and second switch Qυ
.

Since it is synchronized with the switching timing of @, the generation of the erase mode pulse PF means the start of erase.

When the erase motor pulse PE is supplied, the counter θ force is activated and the pulse output from the frequency generator is counted. The erase mode/f pulse pE also operates the subsequent head transport control circuit (b).

This control circuit 0→ is the first control/? generated simultaneously with the input of the erase mode pulse PE. The pulse PC1 moves the magnetic head H toward the outer periphery of the disk θ by an amount corresponding to two steps (see FIG. 9). any 2'
) is controlled by the distribution circuit (c). Then, when the output of the counter G171 becomes an output corresponding to the tube rotation, the second control /? The pulse I'c2 is supplied to the pulse distributor (c) and the /4' pulse power amplifier 0~(
The magnetic head H is driven as desired.
is sequentially advanced by an amount corresponding to two steps (see FIG. 9).

When the output of counter θ is equivalent to m rotations, /
The output of the glucose distributor (a) is stopped.

The same operation as described above occurs when erasing the recorded contents of a track different from the one described above.

In this way, by controlling the pulse distributor, it is possible to shift the erase noise turn TE by a predetermined amount with respect to the recording arm turn T as shown in FIG. Even if the jacket α is inserted eccentrically, there is almost no erasure leakage.

Therefore, deterioration of the methyl image due to partial double recording due to erasure omission can be reliably prevented.

Application Example Although the above-mentioned embodiment exemplifies a disk used in an electronic camera as a sheet-like recording medium, it is possible to use the magnetic head H not only for recording and reproducing but also as an erasing head for other sheet-like recording media. This invention can be applied.

Effects of the Invention As explained above, according to the present invention, the magnetic head for recording and reproducing is also used as an erasing head, so that even when the recording track width and the erasing track width are the same, the magnetic head after tracking adjustment Record H on track T
Since the recorded signal was erased by scanning the outer circumferential side and the inner circumferential side slightly while closing each opening, even if the jacket α→ is inserted with a slight eccentricity, there will be no omission of erasure due to this eccentricity.

Therefore, deterioration in image quality caused by double recording due to omission of erase can be reliably eliminated.

Note that the erasure frequency v1. If the relationship between fvn and reduction ratio n is selected as described above, there will be no beat disturbance based on the cancellation signal, and a sufficient cancellation rate can be obtained, so the cancellation frequency fvn can be set within the band of the video signal SO. No matter which option you choose, you can get high quality methyl images.

Therefore, the present invention is particularly suitable for application to the above-mentioned electronic camera.

[Brief explanation of drawings]

Figure 1 is a conceptual diagram of an electronic camera, Figure 2 is a diagram showing the relationship between a magnetic head and a magnetic disk, Figure 3 is a diagram showing an example of a track pattern, Figure 4 is a frequency spectrum diagram, and Figure 5 is a diagram showing the relationship between a magnetic head and a magnetic disk. A system diagram showing an example of a recording/reproducing apparatus according to the present invention, FIG. 6 is a diagram showing the relationship between rotational speed and erasing rate during erasing, FIG. 7 is a diagram showing the relationship between erasing frequency and erasing rate, and FIG. 9 is a diagram showing the relationship between erasing current and erasing rate, FIG. 9 is an explanatory diagram of an erasing track pattern, and FIG. 10 is a system diagram showing an example of a control circuit for magnetic head transport, which is the main part of the present invention. . H is the magnetic head, (9) is the optical sensor, (b) is the magnetic disk, α→ is the jacket, αQ is the recording/reproducing circuit, 00° (2) is the first and second switch, (2η is the speed control system,
SER is the erase signal, fv, n is the recording erase frequency, fyp
is the reproduction erasure frequency, αη is the pulse motor, θ ~ θ→ is the 41 Rusunoyawarang, (c) is the pulse distributor, θ
0 is a counter, θ→ is a head transport control circuit, and PK is an erase mode pulse. Figure 8. Figure 8 Figure 10

Claims (1)

[Claims] In a recording and reproducing apparatus that records information signals on a sheet-like recording medium using the same magnetic head and reproduces them from the same magnetic head, an erase signal is supplied to the magnetic head during erasing, and the information signal is supplied to the magnetic head after tracking adjustment. A recording/reproducing device characterized in that a recorded signal on a recording track is erased by scanning a magnetic head with a slight shift toward the outer circumference and inner circumference of the recording track.